TO the study of climatic changes in the Europe-North Atlantic region some methods classical to the meteorological community, such as an empirical orthogonal function (EOF) decomposition and analogues searching were combined with methods used by the contemporary theory of dynamical systems. In this paper we try to resolve a question about the nature of changes in the climatic system, starting from an investigation as to whether features of self-similarity typical for strange attractors (SA) remain invariant or break. The essence of our approach is a reconstruction of a coarse-grained dimension of a strange attractor on the basis of time series of meteorological data. The best results were obtained by joint application of the EOF and Takens methods with a local approximation of a strange attractor trajectory by the fixed mass (analogue) method. The presented method has value not only as a research tool and has since October 1944 been implemented operationally at IMWM (Poland) to forecast a half-year air temperature anomaly within the mid-latitude belt.

Crop-growth simulation models need long-term daily weather data to assess possible modifications in farm production in changed climatic conditions. Presented here is a stochastic weather generator LARS-WG that provides synthetic long time series of climatic elements. The generator gave an adequate simulation of weather parameters for a selected station in Poland and was next applied to construct climate change scenarios on the basis of UKTR model data.

This paper discusses the output of Polish climatologists dealing with climate changes. Some results of the studies carried out by A. Pietkiewicz (1889), R. Merecki (1914), J.P. Rychlinski (1923), W. Gorczyñski (1915), H. Arctowski (1934), J. Lambor (1954), E. Romer (1947), W. Okolowicz (1948) et al. are reported.Climatic forecasts for Poland are presented (with the development of the "greenhouse effect" taken into account). These assume that with doubled CO2 concen-tration air temperature in Poland will rise by 2-5°C (Fig. 1). The results of forecasts concerning precipitation are diverse.Circulation factors take part in forming climate fluctuations. The paper presents a 500 hPa configuration determining thermal and precipitation anomalies in Poland (Fig. 2). The duration of circulation epochs and development stages of continental and oceanic features of Poland's climate were compared (Table 1).The analysis of many-year meteorological observations reveals quasi-cyclic climate fluctuations whose spectrum ranges from 2, 3-4, 6, 8, 11, 30, 80 and 180-year periods. The two latter cycles — "secular" and "bisecular" — determine falling temperature trends for the nearest future. On the basis of the observed temperature fluctuations their relationship with the 11-year solar cycle was found (Fig. 3).Research problems concerning the scenario of climate changes for the nearest decades were listed.

Contemporary climatic changes occur on global, regional and local scales. On each of these, changes are shaped by a set of various climatic controls, whose concurrent action has various effects on the functioning of climate in time and space. The climate of the Raba River valley in the period 1971-1992 is presented in this study as an example of the changes that can take place in the character and structure of a local climate. The regional scale trends of air temperature changes for the Carpathian Foothills are presented along with local scale transformation of climatic relations in the Foothill valleys produced by the construction of a reservoir. It is also demonstrated how an analysis of trends in air temperature changes can help detect inhomogeneities in observation series made for different types of topoclimate.

Contemporary climatic changes occur on global, regional and local scales. On each of these, changes are shaped by a set of various climatic controls, whose concurrent action has various effects on the functioning of climate in time and space. The climate of the Raba River valley in the period 1971-1992 is presented in this study as an example of the changes that can take place in the character and structure of a local climate. The regional scale trends of air temperature changes for the Carpathian Foothills are presented along with local scale transformation of climatic relations in the Foothill valleys produced by the construction of a reservoir. It is also demonstrated how an analysis of trends in air temperature changes can help detect inhomogeneities in observation series made for different types of topoclimate.

Based on Krakow's measurement series of air temperature in the 20th century an attempt was made to analyse the winter season by means of some criteria which are important for the thermal conditions which — in turn — influence natural processes and phenomena. The first day with mean daily air temperature <0°C was taken to determine the beginning of a winter and the last such day for the end of winter. The characterization of winters was based on the number of winter days (mean daily air temperature <0°C), the number of frosty days (daily maximum air temperature <0°C), the number of extreme frosty days (daily maximum air temperature <-10°C) and the sums of frost (sums of mean daily air temperature <0°C). Special attention was paid to extreme winters because of their thermal conditions as well as their frequency and variability. It was established that recently observed winters are the mildest in our century and that the concentration of such winters in the 1980s allowed for a link with global warming. The winters in question are inducing environmental changes.

The paper presents the results of a study on the effects of meteorological conditions on the total hydrocarbon concentrations (THC) in the atmosphere where THC denotes the sum of methane and non-methane hydrocarbons. The testing area was contained within the limits of the Gdańsk Refinery located in the eastern part of Gdańsk in the coastal zone of the southern Baltic Sea (Fig. l).The experimen-tal data were collected by the Automatic Air Monitoring System of Gdańsk Refinery, and meteorological parameters were measured at Gdańsk-Świbno synoptic station in a period of 351 days. The data were evaluated with the aim of revealing spatial differen-tiation in THC concentrations in summer and winter (warm and cold seasons) and over the year, as well as to determine the frequency of the average daily concen-tration classes at particular measurement points under specific meteorological con-ditions. Meteorological situations influenc-ing THC concentrations were defined and statistical analysis yielded a quality class-ification of the atmosphere around the Gdańsk Refinery.

The article presents alterations observed in interstitial water chlorinity and (180, D) isotope composition and in near-bottom salinity caused by groundwater discharge to the Puck Bay from Cretaceous, Tertiary and Quaternary aquifers. The groundwater seepage decreases the chlorinity of interstitial water and the salinity of near-bottom water. The comparison of the oxygen and hydrogen isotope composition of underground, interstitial and near-bottom waters indicated a reduction of the content of heavy isotopes in the interstitial water and thus gave evidence of freshwater seepage through the sea floor. Zones with abnormal interstitial water chlorinity and diminished salinity of near-bottom water were used to determine drainage areas for fresh groundwater on the Puck Bay bottom.

The author starts from the assumption that the idea of sustainable development will remain merely an attractive slogan of limited application if it is not given an operational form. It is therefore necessary to search for ways of making it operational. The author suggests two ways he considers promising: one inspired by the theory of economic development and the other by the theory of synergetics. To approach the targets of sustainable development, the present structure of ecological-economic systems requires a pro-ecological transformation. It follows from the theory of economic development that a necessary condition for such a transformation is the discontinuity of the functions of demand, production, saving, and straining and regeneration of the natural environment. Synergetics, in turn, suggests tracing the transition from micro-scale changes to macro-scale ones, and then the transition of complex systems from one level of complexity to another.